Warren Christopher Clark (Abu Mohammad al-Ameriki), originally from Houston, was among five people captured by Syrian Democratic Forces in Syria. He had written a letter offering to help the Islamic State by teaching English overseas.

Warren Christopher Clark (Abu Mohammad al-Ameriki), originally from Houston, was among five people captured by Syrian Democratic Forces in Syria. He had written a letter offering to help the Islamic State by

Warren Christopher Clark (Abu Mohammad al-Ameriki), originally from Houston, was among five people captured by Syrian Democratic Forces in Syria. He had written a letter offering to help the Islamic State by teaching English overseas.

Warren Christopher Clark (Abu Mohammad al-Ameriki), originally from Houston, was among five people captured by Syrian Democratic Forces in Syria. He had written a letter offering to help the Islamic State by

A former Fort Bend substitute teacher who applied to teach English for the Islamic State overseas has reportedly been captured in Syria by Kurdish rebels.

Warren Christopher Clark, 34, who used the nom de guerre Abu Mohammad al-Ameriki, along with five other alleged ISIS supporters, including another American man, an Irish man and two Pakistanis, according to an online news release Sunday from the Syrian Democratic Forces.

A letter ostensibly written by Clark offering his service to the Islamic State was previously obtained by a team of sleuthing counterrorism scholars at George Washington University.

“Rarely are ISIS sympathizers so formal in their offers of support,” said Seamus Hughes, a counterterrorism expert at GWU’s Program on Extremism, who previously served as senior counterterrorism advisor for the U.S. Senate Committee on Homeland Security and Governmental Affairs.

According to a resume previously obtained by the university scholars, Clark graduated from the University of Houston just over a decade ago and was a substitute English as a Second Language teacher in Fort Bend for more than a year before he moved onto similar assignments in Saudi Arabia and Turkey.

Hughes said in an online post Sunday that Clark appeared most interested in helping support the Caliphate — a utopian state building project — unlike some Americans, who sought to join the jihadists in combat after viewing brutal images of civilians impacted by bombings by the Assad regime.

Military officials with Operation Inherent Resolve, the U.S.-led coalition against ISIS militants in Iraq and Syria, knew about the SDF release, but were unable to confirm whether it was accurate, according to Stars and Stripes.

“The incident is under investigation,” Army Col. Scott Rawlinson told the U.S. military publication.

Publicly available federal court records do not indicate that Clark has been charged in the case, but charges in terrorism cases are often kept under seal.

U.S. Attorney Ryan K. Patrick in Houston declined to comment Sunday about whether Clark was being extradited to the Southern District of Texas, which includes Houston.

Hughes, who meticulously tracks cases of homegrown terrorist support through the GMU program, said Clark would be the 15th American to return to the U.S. on federal charges of supporting ISIS.

The Houston region has pursued three cases involving U.S. support for ISIS in recent years and landed two convictions. The case of a third defendant is pending.

Copies of the letter and resume retrieved from a house in Mosul, Iraq — obtained by Hughes and two colleagues at GWU — indicate that Clark wanted a job as an English teacher for Islamic State terrorists. The author, who signs off in his breezy cover letter as Abu Mohammad, says he has “always loved teaching others and learning from others.”

A blurry reprint of the letter was published in a February 2018 report from the Washington D.C. university, “The Travelers: American Jihadists in Syria and Iraq,” by Hughes, Alexander Meleagrou-Hitchens and Bennett Clifford. GWU last year was the first to report that Clark had sent the letter and a resume to the group that became famous for videos of jihadists beheading Americans.

The English-language cover letter, which begins “Dear Director,” adopts the upbeat tone of someone looking for an overseas teaching position.

“As a teacher, it would be my goal to create a supportive classroom environment and to guide my students in building a solid English foundation,” the author writes. “I have a long background in teaching a variety of different subjects and have instructed students of all ages at several schools.”

In the resume, which also appears to be a reproduction, Clark indicates he completed certification with 140 hours of training as an ESL teacher through Oxford Seminars in Houston and worked from January 2009 to November 2011 as a substitute teacher in Sugar Land.

He then taught elementary and intermediate pupils at a construction college in Riyadh, Saudi Arabia between January 2012 and November 2014 and for four months taught “reading, speaking and listening,” to 20 students aged 18 to 40 in Konya, Turkey. The resume does not go beyond June 2015.

A friend of Clark’s told the GWU researchers that they assumed that Clark was an FBI informant because, “No one is that open about liking terrorism,” Hughes wrote in a Lawfare blog post Sunday. Hughes wrote that Clark left Texas to join ISIS but stayed off radar until Mosul was liberated by Iraqi forces in the summer of 2017.

UH spokesman Mike Rosen that Warren Christopher Clark, who majored in political science and minored in global business, graduated from UH in 2007, according to the university registrar. He began his studies in 2003, records indicate. Voting and vehicle records for Fort Bend County show a Warren Christopher Clark of the same age at a Sugar Land address.

“We’re going to see more Americans like Clark returning home to face the consequences of their choices,” said Hughes. “With his time withing the terrorist group, he should have a wealth of information that would be interesting for law enforcement and intelligence officials.”

Gabrielle Banks covers federal court for the Houston Chronicle. Send her tips at gabrielle.banks@chron.com and follow her on Twitter.